content: /**
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * Licensed under the Apache License, Version 2.0 (the "License"); you may not
   * use this file except in compliance with the License. You may obtain a copy of
   * the License at
   *
   * http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
   * License for the specific language governing permissions and limitations under
   * the License.
   */
  
  package io.reactivex.flowable.internal.operators;
  
  import static org.mockito.ArgumentMatchers.any;
  import static org.mockito.Mockito.*;
  
  import java.util.concurrent.*;
  
  import org.junit.Test;
  import org.mockito.invocation.InvocationOnMock;
  import org.mockito.stubbing.Answer;
  import org.reactivestreams.*;
  
  import io.reactivex.common.Schedulers;
  import io.reactivex.flowable.*;
  import io.reactivex.flowable.subscribers.TestSubscriber;
  
  public class FlowableFromCallableTest {
  
      @SuppressWarnings("unchecked")
      @Test
      public void shouldNotInvokeFuncUntilSubscription() throws Exception {
          Callable<Object> func = mock(Callable.class);
  
          when(func.call()).thenReturn(new Object());
  
          Flowable<Object> fromCallableFlowable = Flowable.fromCallable(func);
  
          verifyZeroInteractions(func);
  
          fromCallableFlowable.subscribe();
  
          verify(func).call();
      }
  
      @SuppressWarnings("unchecked")
      @Test
      public void shouldCallOnNextAndOnCompleted() throws Exception {
          Callable<String> func = mock(Callable.class);
  
          when(func.call()).thenReturn("test_value");
  
          Flowable<String> fromCallableFlowable = Flowable.fromCallable(func);
  
          Subscriber<String> observer = TestHelper.mockSubscriber();
  
          fromCallableFlowable.subscribe(observer);
  
          verify(observer).onNext("test_value");
          verify(observer).onComplete();
          verify(observer, never()).onError(any(Throwable.class));
      }
  
      @SuppressWarnings("unchecked")
      @Test
      public void shouldCallOnError() throws Exception {
          Callable<Object> func = mock(Callable.class);
  
          Throwable throwable = new IllegalStateException("Test exception");
          when(func.call()).thenThrow(throwable);
  
          Flowable<Object> fromCallableFlowable = Flowable.fromCallable(func);
  
          Subscriber<Object> observer = TestHelper.mockSubscriber();
  
          fromCallableFlowable.subscribe(observer);
  
          verify(observer, never()).onNext(any());
          verify(observer, never()).onComplete();
          verify(observer).onError(throwable);
      }
  
      @SuppressWarnings("unchecked")
      @Test
      public void shouldNotDeliverResultIfSubscriberUnsubscribedBeforeEmission() throws Exception {
          Callable<String> func = mock(Callable.class);
  
          final CountDownLatch funcLatch = new CountDownLatch(1);
          final CountDownLatch observerLatch = new CountDownLatch(1);
  
          when(func.call()).thenAnswer(new Answer<String>() {
              @Override
              public String answer(InvocationOnMock invocation) throws Throwable {
                  observerLatch.countDown();
  
                  try {
                      funcLatch.await();
                  } catch (InterruptedException e) {
                      // It's okay, unsubscription causes Thread interruption
  
                      // Restoring interruption status of the Thread
                      Thread.currentThread().interrupt();
                  }
  
                  return "should_not_be_delivered";
              }
          });
  
          Flowable<String> fromCallableFlowable = Flowable.fromCallable(func);
  
          Subscriber<String> observer = TestHelper.mockSubscriber();
  
          TestSubscriber<String> outer = new TestSubscriber<String>(observer);
  
          fromCallableFlowable
                  .subscribeOn(Schedulers.computation())
                  .subscribe(outer);
  
          // Wait until func will be invoked
          observerLatch.await();
  
          // Unsubscribing before emission
          outer.cancel();
  
          // Emitting result
          funcLatch.countDown();
  
          // func must be invoked
          verify(func).call();
  
          // Observer must not be notified at all
          verify(observer).onSubscribe(any(Subscription.class));
          verifyNoMoreInteractions(observer);
      }
  
      @Test
      public void shouldAllowToThrowCheckedException() {
          final Exception checkedException = new Exception("test exception");
  
          Flowable<Object> fromCallableFlowable = Flowable.fromCallable(new Callable<Object>() {
              @Override
              public Object call() throws Exception {
                  throw checkedException;
              }
          });
  
          Subscriber<Object> observer = TestHelper.mockSubscriber();
  
          fromCallableFlowable.subscribe(observer);
  
          verify(observer).onSubscribe(any(Subscription.class));
          verify(observer).onError(checkedException);
          verifyNoMoreInteractions(observer);
      }
  }
  